A. Field of the Invention
This invention relates to an endoscope with a channel for inserting a medical instrument and an operating device for raising the distal end portion of the medical instrument which is introduced into the body cavity through the channel.
B. Description of the Prior Art
A typical endoscope has a channel communicating between an operating section and the distal end of an insertion section. Through this channel, a medical instrument such as forceps or a catheter is introduced into the body cavity. A storage room having an opening communicating with the channel is provided in the distal end portion of the insertion section of the endoscope. Stored in this storage room is a raising block for setting a direction in which a medical instrument is introduced into the body cavity.
This raising block is connected to a rotating shaft mounted to the bottom of the storage room. The raising block is connected with a raising operation wire extending from the operating section and is controlled remotely from the operating section. The raising block is stably rotated in a substantially vertical direction as it is guided by the left and right walls of the storage room.
However, in the storage room of the raising block in an ordinary endoscope, one side wall where the raising operation wire is located is relatively low in height. As a result, there is a relatively large space between the top face of the side wall and the raising operation wire. This poses a problem that when a medical instrument is extended into the body cavity through the opening of the storage room, the distal end of the medical instrument enters the space and gets caught by the raising operation wire.
A possible solution to prevent this problem is to raise the height of the side wall very close to the raising operation wire. In this case, however, the resulting increased surface area of the side wall increases the frictional resistance between the side wall face and the raising block, making it difficult to operate the raising block.
In a typical endoscope, as disclosed in Japanese Utility Model Disclosure (Kokai) No. 59-33401, a guide groove for guiding a medical instrument is formed in the top surface of the raising block. Along this guide groove, the distal end of the medical instrument is guided and introduced into the body cavity. The sheath of the medical instrument, however, does not contact the whole length of the guide groove slidingly. The sheath of the medical instrument extended from the storage room into the body cavity slidingly contacts only the distal end edge of the raising block. This means that the medical instrument extended into the body cavity is raised by the distal end edge of the raising block.
As described above, in the conventional raising block, the sheath of a medical instrument which extends from the opening of the storage room is supported by the distal end of the raising block.
The problem with the conventional raising block is that since the sheath of a medical instrument is generally formed of a closely wound coil, when the medical instrument is moved forward and backward while the sheath is supported by the distal end edge of the raising block, the medical instrument sways or moves intermittently each time the coil goes over the edge by one pitch. If the medical instrument moves unstably as mentioned above, it is difficult to bring the distal end of the medical instrument closer to the diseased part in the body cavity. In addition, high-level technique is required and a long time is taken for treatment, increasing the pains of the patient.
When the raising block is turned, the distal end edge of the raising block slides over the sheath of the medical instrument. As a result, the medical instrument vibrates and moves unstably, thus impeding the treatment.